1. Field of the Invention
This invention is directed to composite laminates comprised of a rubbery layer formed from a rubber composition of a selected acrylonitrile copolymer and a fibrous layer formed from a selected organic fiber treated with a specified dip coating, both layers being bonded together into an integral structure. The invention further relates to composite hoses having such rubbery and fibrous layers assembled as constituent parts.
2. Description of Prior Art
Rubber products such as hoses, tires, belts, rolls, shapes and the like have of late found application under oil-stained, elevated temperature and pressure conditions for prolonged periods of time. Fast deterioration of such product literally needs laborious maintenance and replacement and will in some instances lead to serious hazards.
A variety of rubbers are know to be resistant to oil and to heat at from 120.degree. to 150.degree. C. They include acrylonitrile-butadiene rubber (NBR), acryl rubber (ACM), ethylene-acryl rubber (AEM), ethylene-acryl-vinyl acetate rubber (ER), chlorosulfonated polyethylene rubber (CSM), chlorinated polyethylene rubber (CM) and the like and also modified NBR rubbers having their conjugated diene units hydrogenated. To cope with the trend of the users' stricter requirements in regard to heat resistance even at about 170.degree. C., certain acrylonitrile copolymers have been proposed in which the conjugated diene units are hydrogenated at a greater level.
In general, rubber compositions are broadly classifiable into two modes of vulcanization, one of which is sensitive to sulfur and the other to organic peroxide. Peroxide vulcanization is preferred to attain improved heat resistance. From the adhesion point of view, sulfur vulcanization is commonly accepted as many rubber products are usually built of rubber and fiber.
Highly hydrogenated acrylonitrile copolymers are necessarily subjected to peroxide vulcanization. This leaves the problem that such specific rubbers will not sufficiently bond to fibrous material, resulting in a composite laminate of poor structural strength. There has been still much to be desired in making the fullest use of the beneficial effects of those rubbers.